"The '91 videodisc format that someone mentioned earlier was probably
Laserdisc but that was early enough it could have been the Pioneer (?)
format which read the video via a stylus dragged through the grooves on the
disc. There were some production problems with some Laserdiscs that
persisted (in theory) until DVDs came out wherein the picture would crap out
for unknown reasons and the
disc would be a 12" coaster."
Let's get this straight.
There have been many attempts at video recording and playback on disks. John
"Log-head" Baird, the Scottish idiot who promoted mechanically scanned TV in
the '20s and '30s, experimented with recording video on phonograph records.
Westinghouse revived the system in '60s, but for storing still images.
In the '70s Telefunken showed a flexible-disk stylus-read format. (The
stylus didn't actually move; the vertical groove modulations passing the
edge of the stylus excited a "shock wave" that was read by a transducer
attached to the stylus.) The JVC Video High Density (VHD) system used a 12"
disk that was read by a capacitance pickup at the end of what looked like a
conventional tone arm.
Of all these systems, only the JVC made it to market, and only in Japan. It
had some unusual features, such as native support for 3D. There was an audio
version, AHD, that was killed by CD. I don't know if AHD players and disks
were actually sold.
In the US, there were three successful videodisc systems. The first was
LaserVision (LV), developed primarily by Philips (though the system
represents a conglomeration of patents from many companies, including MCA
and Zenith). It appeared in 1977 or 1978, and for the next 20 years was a
modest success, especially among videophiles.
The reason was not the ungainly 12" disks (which in size and "heft" were
reminiscent of 78s), but the terrific picture quality. LV reproduced the
full NTSC signal, with a luminance bandwidth as wide as 5MHz. An LV image
was almost always miles ahead of SmearVision (James Cameron's designation
for VHS); you had to be blind not to see the difference. Around 1986 the LV
system was modified to include two channels of CD-format digital sound,
without any reduction in picture quality or loss of the two existing FM
audio channels.
The problem with LV is that the disks are difficult to manufacture. Maximum
playing time was one hour per side, so movies required two sides, which had
to be pressed and aluminized separately, then glued together!
For a period of about one year in the late '80s, poor gluing and
contamination caused deterioration of the aluminum layer, producing noise
and other image artifacts, derogatorily designated "laser rot." The problems
were eventually resolved. Barring eventual glue deterioration, LVs appear to
be as stable as any other optical medium.
Although LV was not a Pioneer invention, Pioneer did more than everyone else
combined to promote and support the format. They set up their own pressing
plants, released special editions of limited-interest material, and added
digital sound. I have an extensive LV library that includes many titles that
are unlikely ever to be reissued on DVD. Now, if I can just keep my player
working...
The second successful videodisk system was RCA's Capacitance Electronic Disk
(CED). RCA had worked on it since the late '60s or early '70s. In its
original version you handled and played the recordings just like a regular
phonograph record. The final version stored the disk in a caddy to protect
it from dust and scratches.
The CED was groove-based, but the groove was not mechanically modulated; it
was just a guide for the stylus. The actual modulation was produced by
varying the thickness of conductive material under the groove. This
variation produced changes in the capacitance "seen" by an electrode on the
stylus. Hence the system name.
CED image quality fell somewhere between VHS and LV, with resolution
slightly better than the former, and color not much inferior to the latter.
Its principal problem was skipping (which could usually, but not always, be
corrected by replaying the affected area several times) and a finite number
of playbacks (around 1000) before noise rose to an unacceptable level. CED
was the last major consumer-electronics product designed and manufactured in
the US.
The third successful videodisk system is DVD. It appears to resolve all the
problems -- including consumer acceptance -- that plagued preceding systems.
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